ما أفضل كتاب عن كيفية التوبة؟

Among the best writings on repentance, its conditions, its manner, and its issues are:

1. What Ibn al-Qayyim wrote in "Madarij al-Salikin". 2. The chapter related to repentance in "Ihya' 'Ulum al-Din" by Al-Ghazali. 3. The book "Al-Tawbah ila Allah" (Repentance to Allah) by Sheikh Salih Al-Sadlan.